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Zinc-Nickel Plating

The preferred alloy composition for zinc-nickel plating is 12 – 15% nickel, with the remainder being zinc. This alloy gives exceptional sacrificial corrosion resistance and can be readily passivated. To achieve this alloy, zinc-nickel is usually plated from an alkaline electrolyte. For some applications, including the plating of brake castings, acid zinc-nickel can be used.

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Coating advantages

New product - enviralloy nispeed

Advantages of MacDermid zinc-nickel plating processes

 

Zinc nickel platingZinc-nickel plating is the choice for high performance coatings in automotive applications. Enviralloy NiSpeed is the process of choice for zinc-nickel applicators who demand high deposition rates from their alkaline plating solutions.

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 ZinKlad brochure

 

MacDermid Zinc-Nickel Plating Systems

 

Product                            Solution typeDescription
Enviralloy Ni 12-15 Alkaline Wheel bolt zinc-nickel platingProduces zinc-nickel alloys with a nickel content of 12-15%. The process is easy to operate and control in volume production and is suited to both rack and barrel applications. Under optimum conditions, its high cathode efficiency ensures that fast plating rates can be achieved without high current density burning, dramatically improving production output.
Enviralloy NiFlex 12 Alkaline zinc-nickel plating tubesDesigned primarily for zinc-nickel plating components which are post-plate deformed, such as fluid transfer tubes. Enviralloy Niflex 12 produces a semi-bright zinc-nickel deposit with a consistent alloy composition in the range within 12 - 15% nickel and good thickness distribution across a wide range of current densities and operating conditions.
Enviralloy NiSpeed Alkaline Zinc nickel platingEnviralloy NiSpeed is a rack process with high cathode efficiency. This helps to ensure fast zinc-nickel plating rates and improved production yields. Enviralloy NiSpeed yields a consistent nickel content of 12-15% across a wide range of current densities and operating conditions.
Kenlevel Ni 12-15 Acid zinc-nickel plating calipersKenlevel Ni 12-15 avoids the need for 'duplex' coatings normally applied when plating brake calipers in alkaline based zinc-nickel. It offers substantial benefits over earlier acid zinc-nickel plating alloy technology, namely consistency in both deposit and alloy distribution; critical when zinc-nickel plating complicated castings.

 

Applications

Zinc-nickel plating is usually applied where specifiers want the highest performance with the lowest deposit thickness. By specifying zinc-nickel, components can resist more than 1000 hours neutral salt spray (ISO 9227 & ASTM B117) with no effect on the dimensional tolerance of threaded components. Components typically plated with zinc-nickel include:

  • Automotive – Fluid transfer tubes which can be deformed into their required shape after plating
  • Automotive – Fasteners, particularly in areas of high corrosion (underhood, chassis joints)
  • Electronic – Connectors, as a direct replacement for cadmium to provide corrosion resistance and high electrical conductivity
  • Aerospace and defense – Joining components in contact with aluminum.

Zinc nickel platingTo meet these industry requirements, specifiers request ZinKlad 1000. By demanding this coating, leading automotive companies receive zinc-nickel plating finished by an approved applicator.

Post-plate Passivation

Zinc-nickel deposits are passivated to further enhance the corrosion resistance of the deposit. Recent legislation including End of Life Vehicle Directive (ELV) and Restriction of the use of certain Hazardous Substances (RoHS) has led to new, high performance, passivation systems based on trivalent chromium.

Topcoats

 

Finally a topcoat can be applied to the zinc-nickel plating and trivalent passivation coatings. The choice of topcoat depends on the application.

zinc-nickel plating bolts

Advantages of topcoats include:

  • Predictable torque and tension characteristics
  • Improved corrosion resistance after post-plating deformation operations
  • Resistance to thermal shock (heat exposure) testing